Tutorial: Point, Station, Trajectory Observation Datatypes

An observation is a collection of measurements at one time and location. Several types of observation collections are described in the Common Data Model's Scientific Datatype layer. A Point Observation dataset contains observations which are not necessarily related in space or time. A Station Observation dataset contains time series of observations at named locations called stations. A trajectory is a collection of observations which are connected along a one dimensional track in space, with time increasing monotonically along the track. A Trajectory Observation dataset contains one or more trajectories.

Opening a Point, Station, or Trajectory Dataset

The correct way to open a PointObsDataset is to use the TypedDatasetFactory class. This allows third parties to plug-in alternative imlpementations of PointObsDataset, StationObsDataset, or TrajectoryObsDataset at runtime. (Note: The TypedDatasetFactory superceeds the PointObsDatasetFactory and TrajectoryObsDatasetFactory.)

Here is some example code for opening a point dataset: 

  StringBuffer errlog = new StringBuffer();
  ucar.nc2.dt.PointObsDataset ds = (ucar.nc2.dt.PointObsDataset)
  ucar.nc2.dt.TypedDatasetFactory.open( thredds.catalog.DataType.POINT,
                                        location, cancelTask, errlog);
  if (null == ds) 
    throw Exception("Cant open PointObsDataset at location= "+location+"; error message= "+errlog);

If the data type is not known ahead of time, call TypedDatasetFactory.open() with null as the first argument.

Example Station Dataset

In ToolsUI:
Station Map


Example Trajectory Dataset

 In ToolsUI:

Trajectory Map